The invention relates generally to quantum key distribution (QKD). In particular, the invention relates to a QKD protocol that employs weak measurements to inhibit eavesdropping.
Secure key distribution constitutes an important element in reliable communication, and remains the focus of technological innovation, as represented by U.S. Pat. No. 8,391,486. Communication scenarios involve three participants: transmitter Alice, recipient Bob, and eavesdropper Eve. Alice desires to send a secure message to Bob using cryptography, while Eve attempts to intercept Alice's message. C. H. Bennett and G. Brassard described their BB84 protocol in “Quantum Cryptography: Public Key Distribution and Coin Tossing”, Proceedings of the IEEE International Conference (1984), available at http://www.cs.ucsb.edu/˜chong/290N-W06/BB84.pdf. A video description can be viewed at http://www.youtube.com/watch?v=UVzRbU6y7Ks. Subsequent protocols include E91 by A. Ekert, “Quantum cryptography based on Bell's theorem”, Physical Review Letters 67 (6), 667 (1991), and BBM92 by C. H. Bennett, G. Brassard and N. D. Mermin, “Quantum Cryptography without Bell's Theorem”, Physical Review Letters 68 (5), 557 (1992). BB84 represents a widely accepted conventional process to attempt secure communication.